How to auto-adjust intersection plane ?

Hi all, I have a slice plane to cut the object. Currently, the slice plane is either infinite or I have to manually adjust its size. I want to auto-adjust the size of the slice plane according to the size of intersection planes. I've add a figure for demonstration. I've done a lot of searches and try but still have no idea. Can anyone give some hints or help? I don't want to use Shaders, I need the actual plane. Besides, @Bunny83 if I can get some help from you? Thanks!